Association between different attributes of physical activity and fat mass in untrained, endurance- and resistance-trained men

The objective of this cross-sectional study was to assess different attributes of physical activity and fitness and their relationship to nutritional state in endurance- and resistance-trained, compared to untrained men. The subjects were 42 men matched for age, of which 13 were untrained [UT, mean age 30.2 years, mean height 180.7 cm, mean body mass 83.6 kg, mean body mass index (BMI) 25.6 kg·m^–2], 14 were endurance-trained athletes (ET, mean age 29.6 years, mean height 178.4 cm, mean body mass 74.0 kg, mean BMI 23.2 kg·m^–2) and 15 were resistance-trained athletes (RT, mean age 28.4 years, mean height 183.4 cm, mean body mass 94.1 kg, mean BMI 27.4 kg·m^–2). Fat mass (FM), fat free mass (FFM), muscle mass (MM) and total body water (TBW) were assessed using anthropometry and bioelectrical impedance analysis. Resting energy expenditure was measured by indirect calorimetry (IC) and total energy expenditure (TEE) by a combination of IC and individually calibrated 24-h heart-rate monitoring. The activity related energy expenditure (AEE) and the physical activity level were calculated. Movements were assessed using pedometry. Aerobic fitness was determined using ergometry, muscle strength [quadriceps muscle (Fa_max), ischiocruralis muscle (Fb_max), biceps muscle (Fc_max), triceps muscle (Fd_max)] by computer tensiometry. Different time domain indexes of heart rate variability (HRV) were examined during sleep, rest and the whole day as an index of sympathetic nervous system (SNS) activity. When compared with UT and RT, ET had reduced body masses and FM, but increased percentage TBW (P<0.05 and P<0.01, respectively). FFM and MM were increased in RT, when compared with UT and ET (P<0.01). ET had higher TEE, AEE, pedometry derived activities, oxygen consumption and power during vigorous exercise than RT and UT (P<0.05 and P<0.01, respectively). Respiratory exchange ratio at moderate exercise intensities was increased in RT (P<0.05). In the 12 time domain indexes of HRV 6 and 10 were higher in ET than in RT and UT respectively (P<0.05 or P<0.01, respectively) suggesting an increased SNS activity in ET. By contrast, Fa_max, Fc_max and Fd_max were elevated in RT (P<0.01). FM was negatively associated with aerobic fitness, but not with muscle strength. We concluded that the physiological and metabolic adaptations to exercise and nutritional state differ between ET and RT subjects. Participation in RT results predominantly in changes in body composition and strength but not in energy expenditure, movements and SNS activity. The opposite was the case for ET. Aerobic fitness, physical activity, movements and activity of SNS were all increased but body mass and FM were decreased. The latter finding may support the idea that, with regard to possible health benefits, ET is more effective than RT. Electronic Publication     

Physiological consequences of acculturation: a 20-year study of fitness in an Inuit community

Surveys in 1969/1970, 1979/1980, and 1989/ 1990 assessed physical fitness among adult Inuit living in Igloolik, Northwest Territories, Canada, during a period of rapid acculturation to a sedentary lifestyle. MANOVA for age, cohort, and age-cohort effects indicated significant trends to greater skinfold readings [male (M) and female (F)] and body mass (F only), a lower handgrip and knee extension force (M and F), and lower step test predictions of aerobic power (M and F) in the more recent cohorts, with no change of forced vital capacity, 1-s forced expiratory volume, or hemoglobin level. By 1989/1990, continuing hunters tended to have thicker skinfolds than other villagers, and showed no advantage of aerobic power. The average fitness of the sample when tested in 1989/1990 was comparable with that of sedentary populations in Southern Canada, but a minority of villagers who now practiced regular sport had conserved the high levels of fitness that were observed in 1969/1970. We conclude that the fitness of this community appears to have deteriorated markedly as it has become more sedentary, and we thus recommend that health authorities develop methods of promoting an active lifestyle that are culturally appropriate to the populations of circumpolar settlements.     

Back extensor muscle oxygenation and fatigability in healthy subjects and low back pain patients during dynamic back extension exertion

The purpose of this study was to assess if chronic low back pain patients have impaired paraspinal muscle O₂ turnover and endurance capacity as compared to healthy control subjects during dynamic exercise. Middle-aged healthy male subjects (n = 12, control) and male patients with chronic low back pain (n = 17, CLBP) participated in the study. L4–L5 level paraspinal muscle fatigue was objectively assessed during earlier validated 90 s dynamic back endurance test (spectral EMG, MPF_slope). Also EMG amplitude (EMG_amplitude) and initial MPF (MPF_initial) were assessed from the initial 5 s of the endurance contraction. Simultaneously near infrared spectroscopy (NIRS) was used for quantitative measurement of local L4–L5 paraspinal muscle O₂ consumption. Subcutaneous tissue thickness (ATT) was measured from the EMG and NIRS recording sites. The results indicated that control and CLBP groups were compatible as regarding anthropometric variables, paraspinal muscle activation levels (EMG_amplitude), initial MPF (MPF_initial) and ATT. When the ATT was used as a covariate in the ANOVA analysis, CLBP group did not show significantly greater paraspinal muscle fatigability (right MPF_slope – 12.2 ± 10.7%/min, left right MPF_slope – 12.6 ± 13.3%/min) or O₂ consumption (right NIRS_slope – 52.8 ± 79.6 μM/l/s) as compared to healthy controls (right MPF_slope – 11.9 ± 7.6%/min, left MPF_slope – 12.7 ± 8.6%/min, right NIRS_slope – 53.7 ± 95.2 μM/l/s). As a conclusion, these CLBP male patients did not show any impaired rate of paraspinal muscle oxygen consumption or excessive paraspinal muscle fatigability during dynamic exercise as compared with healthy controls. Subcutaneous tissue thickness has a strong influence on the NIRS and EMG amplitude measurements and, if unchecked, it could result in the false interpretation of the results.     

Comparison of isokinetic and isoinertial lifting tests as predictors of maximal lifting capacity

Summary This study compared the relationship between isokinetic lifting test (ILT) performance and a maximal operational lifting test (OLT) with that between an isoinertial progressive lifting test (PLT) and OLT. Fifty subjects performed the ILT, PLT and OLT after familiarization trials. OLT was defined as the weight of the heaviest crate that could be lifted to 1.34 m with a progressive, incremental test. ILT performance was the force generated during a single maximal simulated lift on an isokinetic dynamometer. PLT performance was the maximal weight lifted to 1.52 m with a progressive, incremental protocol on a weight stack. OLT was highly correlated with ILT (r=0.96) and PLT (r=0.97); the standard error was similar for both linear regression equations. The results demonstrate that a single maximal voluntary lift on an isokinetic dynamometer is as good a predictor of OLT as in the PLT presently used in military recruit centers.     

Physical demands in working life and individual physical capacity

The purpose of this study was to investigate the prevalence of the excess of metabolic level (metabolic demands in work exceeding one-third of the individual's aerobic capacity) of working men and women today and to describe the population whose metabolic level is exceeded. A second aim was to explore how externally assessed metabolic demands match with the physical function and capacity of working men and women in jobs with the lowest and the highest demands. The aerobic power of each individual (94 men and 94 women) was estimated from heart rate and workload in sub-maximal tests from dynamic legwork on a cycle ergometer. Physical activity was assessed using a task-oriented interview technique. Physical function was measured by tests of muscle endurance in arms, abdomen and legs, handgrip pressure, balance and coordination. The calculation of individual metabolic demands during a "typical working day" showed that 27% of the men and 22% of the women exceeded their metabolic level. The results indicate that the physical fitness is low or somewhat low for two-thirds of the 94 men and for more than one-half of the 94 women. Women in the group with the highest job demands had significantly lower muscle endurance in the abdomen and legs and worse coordination than women in the group with the lowest job demands. Metabolic demands in working life today remain high. This is reflected in a mismatch between individual physical capacity and the physical demands of work for 25% of the population.     

Serum hormones and physical performance capacity in young boy athletes during a 1-year training period

Summary Serum hormones and physical performance capacity in boy athletes (AG;n = 19) were investigated during a 1-year training period (between the ages of 11.6 and 12.6 years). Six young untrained boys served as the control group (CG). The mean serum testosterone concentration increased significantly in AG (P<0.05) following the training period from 2.92 nmol·l^–1, SD 1.04 to 5.81 nmol·l^–1, SD 1.33. Significant differences were not observed in the cortisol, sex hormone binding globulin and growth hormone levels during the follow-up period. The AG clearly increased speed (P<0.001), speed-strength (P<0.01-P<0.001) and anaerobic capacity (P<0.001) whereas CG had only slight increases (NS) in physical performance capacity during a 1-year period. During the last 6-month training period significant positive correlations (r=0.490–0.58;P<0.05 -P<0.01) were observed in AG between the relative changes in testosterone, testosterone: cortisol ratio and growth hormone and the relative performance change in speed, maximal isometric force and endurance, respectively. At the end of the period significant positive correlations were observed in all subjects between the level of testosterone and speed-strength (r=0.52–0.64;P<0.01 -P<0.001) and anaerobic capacity (r=0.49;P<0.05). It was concluded that an increase in anabolic activity with the synchronous training already has positive effects on trainability and physical performance capacity at an early stage in puberty.     

Physical activity and 5-year changes in physical performance tests and bone mineral density in postmenopausal women: the Yokogoshi Study

Objective

The effect of physical activity on musculoskeletal health in older adults is not completely understood. The aim of this study was to determine the relationship between physical activity and 5-year changes in physical performance tests and bone mineral density (BMD) in postmenopausal women.

Study design

The design was a 5-year cohort study.

Main outcome measures

Subjects were 507 women (55-74 years old) living in a rural community in Japan. Physical activity assessed included housework, farm work, and moderate leisure-time physical activity within the previous week. Measurements at baseline included handgrip strength, walking time (timed “Up & Go” test) and BMD of the femoral neck and vertebrae. Five-year changes in these measures (outcome variables) were compared among groups with different levels of physical activity by analysis of covariance.

Results

Women who did not do housework performed worse in changes in handgrip strength (difference = 2.22 kg, P = 0.0201) and worse in changes in the walking time (difference = 0.54 s, P = 0.0072) than those who did housework alone. Women who spent at least 9 h per week (median = 24) doing farm work performed better in changes in handgrip strength (difference = 0.28 kg, P = 0.0334), but worse in changes in the walking time (difference = 0.66 s, P < 0.0001) than those who did not do farm work. However, leisure-time activity was not associated with changes in any outcome variable, and none of the physical activities predicted BMD changes.

Conclusions

Engaging in housework and farm work are determinants of physical function in postmenopausal women, which may help them maintain independence in daily living.     

Urge-to-cough and dyspnea conceal perception of pain in healthy adults

Although dyspnea has been shown to attenuate pain, whether urge-to-cough, a respiratory sensation preceding cough, exerts a similar inhibitory effect on pain has not been clarified. We examined the effects of both urge-to-cough and dyspnea on pain induced by thermal noxious stimuli. Urge-to-cough was induced by citric acid challenge and dyspnea was induced by external inspiratory resistive loads. During inductions of two respiratory sensations, perception of pain was assessed by thermal pain threshold (TPTh) and tolerance (TPTo). TPTh and TPTo were significantly increased accompanied by increases in perception of both urge-to-cough and dyspnea. Fractional change in TPTh during dyspnea was significantly correlated with that during urge-to-cough. Fractional change in TPTo during dyspnea was significantly correlated with that during urge-to-cough. The study suggests that both two distinct respiratory sensations, i.e., urge-to-cough and dyspnea may harbor perception of pain. Further studies investigating interactions among these sensations in clinical settings are warranted.     

Experimental muscle pain modulates muscle activity and work performance differently during high and low precision use of a computer mouse

The aim was to investigate the influence of experimental muscle pain on performance and upper extremity muscle activity during occupational work requiring different levels of precision. Experimental muscle pain was induced by infusing hypertonic saline (0.3 ml, 5% NaCl) into the extensor carpi ulnaris (ECU) muscle. The same amount of isotonic saline was infused on a separate day to act as a control. Tasks requiring use of a computer mouse with high and low levels of precision were performed during the two sessions. Electromyographic (EMG) activity was measured from the ECU, the flexor carpi radialis (FCR) and the trapezius muscles. A group of 13 men participated in the study. Performance measured as work cycle time, cursor movements on the screen, and velocity of cursor movement were unaffected by muscle pain. The ECU muscle pain did not modulate EMG profiles of either the trapezius or FCR muscles – either during high or during low precision work. During the low precision work the painful ECU muscle showed lower EMG activity in specific phases of the work cycle (highest activity phases) compared to the control session (P < 0.05), whereas during the high precision work, experimental pain had no effect on the activity of the ECU muscle. In conclusion experimental muscle pain seems to modulate motor control differently depending on the precision level of the task. This may be of importance for our understanding of why some tasks lead to chronic musculoskeletal disorders. Accepted: 29 August 2000     

TTM-based motivational counselling does not increase physical activity of low back pain patients in a primary care setting--A cluster-randomized controlled trial

OBJECTIVE: To investigate the effectiveness of a TTM-based motivational counselling approach by trained practice nurses to promote physical activity of low back pain patients in a German primary care setting. METHODS: Data were collected in a cluster-randomized controlled trial with three study arms via questionnaires and patient interviews at baseline and after 6 and 12 months. We analysed total physical activity and self-efficacy by using random effect models to allow for clustering. RESULTS: A total of 1378 low back pain patients, many with acute symptoms, were included in the study. Nearly 40% of all patients reported sufficient physical activity at baseline. While there were significant improvements in patients' physical activity behaviour in all study arms, there was no evidence for an intervention effect. CONCLUSION: The outcome may be explained by insufficient performance of the practice nurses, implementation barriers caused by the German health care system and the heterogenous sample. PRACTICE IMPLICATIONS: Given the objective to incorporate practice nurses into patient education, there is a need for a better basic training of the nurses and for a change towards an organizational structure that facilitates patient-nurse communication. Counselling for low back pain patients has to consider more specificated aims for different subgroups.     

Defining knee pain trajectories in early symptomatic knee osteoarthritis in primary care: 5-year results from a nationwide prospective cohort study (CHECK)

Background

GPs have high consultation rates for symptoms related to knee osteoarthritis (OA). Many risk factors for symptomatic knee OA progression remain unknown.

Aim

To define distinct knee pain trajectories in individuals with early symptomatic knee OA and determine the risk factors for these pain trajectories.

Design and setting

Data were obtained from the multicentre prospective Cohort Hip and Cohort Knee study in the Netherlands. Participants with knee OA, according to the clinical criteria of the American College of Rheumatology, and a completed 5-year follow-up were included.

Method

Baseline demographic, anamnestic, and physical examination characteristics were assessed. Outcome was annually assessed by the Numeric Rating Scale for pain. Pain trajectories were retrieved by latent class growth analysis. Multinomial logistic regression was used to calculate relative risk ratios.

Results

In total, 705 participants were included. Six distinct pain trajectories were identified with favourable and unfavourable courses. Statistically significant differences were found in baseline characteristics, including body mass index (BMI), symptom severity, and pain coping strategies between the different trajectories. Higher BMI, lower level of education, greater comorbidity, higher activity limitation scores, and joint space tenderness were more often associated with trajectories characterised by more pain at first presentation and pain progression — compared with the reference group with a mild pain trajectory. No association was found for baseline radiographic features.

Conclusion

These results can help differentiate those patients who require more specific monitoring in the management of early symptomatic knee OA from those for whom a ‘wait-and-see’ policy seems justifiable. Radiography provided no additional benefit over clinical diagnosis of early symptomatic knee OA in general practice.     

Prediction of physical activity level in adulthood by physical characteristics,physical performance and physical activity in adolescence: an 11-year follow-up study

The purpose of the study was to investigate to what extent the physical activity pattern in adulthood can be predicted by physical characteristics, performance and activity in adolescence. A group of 62 men and 43 women completed a questionnaire concerning physical activity during their leisure time at the ages of 16 and 27 years. An activity index produced from the questionnaire. At the age of 16 years, the subjects were also tested for strength (strength test battery) and running performance (9-min run). Maximal oxygen uptake ( ) was estimated from a submaximal test and a muscle biopsy specimen was taken and analysed for fibre types (percentages of types I, IIA, 1113). The proportion of subjects engaged in some kind of physical activity during their leisure time was approximately 70% among the women and 80% among the men at both ages. The time spent on physical activity (minutes per week) decreased with age for the men but not for the women. The women devoted less time. to physical activity than the men both at age 16 and 27 years. The attitude to endurance activities had changed to a more positive attitude among the women and to a less positive attitude among the men at age 27 years. The aerobic potential ( and percentage of type I fibre), running performance, strength performance, physical activity and marks in physical education at age 16 years explained 82% of the physical activity level in adulthood for the women and 47% for the men. The aerobic potential at age 16 years alone explained 31% of the adult physical activity level in the women and 24% in the men. Strength performance, physical activity and marks in physical education at age 16 years further increased the predictive value for the physical activity level in adulthood for the women but not for the men. It is suggested that the major portion of the variation in physical activity level in adult women, but not in the adult men, could be predicted from physical characteristics, physical performance, and the activity level in adolescence.     

Trajectories of physical functioning and their prognostic indicators: A prospective cohort study in older adults with joint pain and comorbidity

Objectives

This study aimed to identify and characterize homogeneous subgroups of individuals with distinct trajectories of physical functioning (PF) and to examine prognostic indicators of deterioration in PF in a highly heterogeneous population of older adults with joint pain and comorbidity.

Study design

A prospective cohort study among 407 older adults with joint pain and comorbidity provided data over a period of 18 months, with 6 month time-intervals. We used latent class growth modelling (LCGM) to identify underlying subgroups (clusters) with distinct trajectories of PF. Next, we characterized these subgroups and applied multivariable logistic regression analysis to identify prognostic indicators for deterioration in PF.

Main outcome measures

We measures PF with the RAND-36 PF subscale and several potential sociodemographic, physical and psychosocial prognostic indicators.

Results

LCGM identified three clusters. Cluster 1 ‘good PF’ contained 140 participants with good baseline PF and small improvements over time. Cluster 2 ‘moderate PF’ contained 130 participants with moderate baseline PF and deterioration over time. Cluster 3 ‘poor PF’ contained 137 participants with poor baseline PF and deterioration over time. After backward selection, the final model that could best distinguish between improved participants (cluster 1) and deteriorated participants (cluster 2–3) included the following prognostic indicators: higher age, more depressive symptoms, less perceived self-efficacy and more activity avoidance.

Conclusions

Older adults with joint pain and comorbidity either improved or deteriorated in PF over time. The prognostic model facilitates the classification of patients, the provision of more accurate information about prognosis and helps to narrow the focus to the high risk group of poor PF.     

A comparative study of coping among women with fibromyalgia, neck/shoulder and back pain

Passive coping strategies for pain (e.g., eatastrophizing) have been implicated in the development and maintenance of chronic pain conditions such as fibromyalgia (FM). Catastrophizing may thus be independently associated with FM, controlling for pain parameters such as intensity and complexity. This cross-sectional study compared coping strategies for pain (Coping Strategies Questionnaire; CSQ) among women with FM (n = 81), neck/shoulder pain (re = 76), and back pain (re = 131). Soeiodemographics and pain parameters were also assessed. FM patients reported stronger pain intensity, higher consumption of analgesics and sedatives, and higher disability than the other patients did. They also reported higher scores for the CSQ subscales–diverting attention, eatastrophizing, praying/hoping, and pain behaviors–and lower scores for self-efficacy beliefs. Multivariate analyses controlling for relevant conifounders ruled out most differences in coping strategies between groups, with the exception of diverting attention and pain behaviors. The results indicate that passive coping is not independently related to FM, but is, rather, dependent on a more general dysfunction due to pain.     

Muscle strength according to level of physical exercise and educational background in middle-aged women in Finland

Summary The aim of this study was to examine the role of socio-economic status and the practice of physical exercise in explaining variation in muscle strength in 50 to 60-year-old women. Consequently, four study groups combining education and physical activity were formed: (1) university education, physically active; (2) university education, sedentary; (3) vocational or lower level of education, physically active; (4) vocational or lower level of education, sedentary. Maximal isometric strength of hand grip, arm flexion, body flexion and extension as well as dynamic power of the abdominal muscles were measured in 112 women. The results of the maximal isometric strength measurements were standardised by body mass index. The means of the maximal isometric strength results and sit-up tests were compared between the groups using two-way analysis of variance. The physically active women performed better than the sedentary in both the isometric and dynamic tests. Greater muscle strength was also found among the more highly educated compared with the less educated. The less educated sedentary women showed the poorest performance in the strength tests.     

Physical activity and healthy ageing: A systematic review and meta-analysis of longitudinal cohort studies

BackgroundOlder people constitute a significant proportion of the total population and their number is projected to increase by more than half by 2030. This increasing probability of late survival comes with considerable individual, economic and social impact. Physical activity (PA) can influence the ageing process but the specific relationship with healthy ageing (HA) is unclear.MethodsWe conducted a systematic review and meta-analysis of longitudinal studies examining the associations of PA with HA. Studies were identified from a systematic search across major electronic databases from inception as January 2017. Random-effect meta-analysis was performed to calculate a pooled effect size (ES) and 95% CIs. Studies were assessed for methodological quality.ResultsOverall, 23 studies were identified including 174,114 participants (30% men) with age ranges from 20 to 87 years old. There was considerable heterogeneity in the definition and measurement of HA and PA. Most of the identified studies reported a significant positive association of PA with HA, six reported a non-significant. Meta-analysis revealed that PA is positively associated with HA (ES: 1.39, 95% CI = 1.23–1.57, n = 17) even if adjusted for publication bias (ES: 1.27, 95% CI = 1.11–1.45, n = 20).ConclusionsThere is consistent evidence from longitudinal observational studies that PA is positively associated with HA, regardless of definition and measurement. Future research should focus on the implementation of a single metric of HA, on the use of objective measures for PA assessment and on a full-range of confounding adjustment. In addition, our research indicated the limited research on ageing in low-and-middle income countries.     

Changes in male exercise performance and anthropometric variables between the ages of 19 and 30

Summary In order to study possible changes in Swedish men between the approximate ages of 19 and 30, 55 men from the Stockholm area were re-examined 11 years after examinations made in connection with compulsory military duty. The most pronounced finding was a 11% increase in body weight accompanied by a 19% increase in waist circumference and a 25–41% increase in skinfold thickness. A 5% increase in work output at heart rate 170 (W ₁₇₀) was observed but the ratio W ₁₇₀/weight decreased by 5%. The observed changes were even more pronounced in a subgroup who had a low exercise level in their spare time at the age of 19 as well as 30.Growth was not quite completed at the age of 19. Of the increase in height amounting to 1.3 cm, 70% was due to growth in tibial length.     

Effect of creatine supplementation on metabolism and performance in humans during intermittent sprint cycling

This double blind study investigated the effect of oral creatine supplementation (CrS) on 4 × 20 s of maximal sprinting on an air-braked cycle ergometer. Each sprint was separated by 20 s of recovery. A group of 16 triathletes [mean age 26.6 (SD 5.1) years. mean body mass 77.0 (SD 5.8) kg, mean body fat 12.9 (SD 4.6)%, maximal oxygen uptake 4.86 (SD 0.7) l · min⁻¹] performed an initial 4 × 20 s trial after a muscle biopsy sample had been taken at rest. The subjects were then matched on their total intramuscular creatine content (TCr) before being randomly assigned to groups to take by mouth either a creatine supplement (CRE) or a placebo (CON) before a second 4 × 20 s trial. A muscle biopsy sample was also taken immediately before this second trial. The CrS of 100 g comprised 4 × 5 g for 5 days. The initial mean TCr were 112.5 (SD 8.7) and 112.5 (SD 10.7) mmol · kg⁻¹ dry mass for CRE and CON, respectively. After creatine loading and placebo ingestion respectively, CRE [128.7 (SD 11.8) mmol · kg⁻¹ dry mass] had a greater (P=0.01) TCr than CON [112.0 (SD 10.0) mmol · kg⁻¹ dry mass]. While the increase in free creatine for CRE was statistically significant (P=0.034), this was not so for the changes in phosphocreatine content [trial 1: 75.7 (SD 6.9), trial 2: 84.7 (SD 11.0) mmol · kg⁻¹ dry mass, P=0.091]. There were no significant differences between CRE and CON for citrate synthase activity (P=0.163). There was a tendency towards improved performance in terms of 1 s peak power (in watts P=0.07; in watts per kilogram P=0.05), 5 s peak power (in watts P=0.08) and fatigue index (P=0.08) after CrS for sprint 1 of the second trial. However, there was no improvement for mean power (in watts P=0.15; in watts per kilogram P=0.1) in sprint 1 or for any performance values in subsequent sprints. Our results suggest that, while CrS elevates the intramuscular stores of free creatine, this does not have an ergogenic effect on 4 × 20 s all-out cycle sprints with intervening 20-s rest periods. Accepted: 2 October 2000     

Anxiety and psychosocial stress as predictors of headache and abdominal pain in urban early adolescents

Objective To examine the relations among anxiety, psychosocialstress, and headache and abdominal pain complaints within thecontext of the Biobehavioral Model of Pediatric Pain. MethodsAdolescents from urban schools serving a predominantly African-Americanpopulation completed measures of pain, anxiety, witnessing violence,problem situations, and victimization at the end of the seventhgrade (N = 502) and 6 months later (longitudinal N = 289). ResultsA high prevalence of weekly headaches (40%) and abdominal pain(36%) was reported. Anxiety partially mediated relations betweenpsychosocial stress and pain at Time 1, particularly for problemsituations. Longitudinal models showed that adolescents reportinghigher levels of pain at Time 1 reported greater increases invictimization and anxiety at Time 2. Changes in pain were positivelycorrelated with changes in anxiety and stress variables. ConclusionsImplications for understanding the causes and correlates ofheadache and abdominal pain in normal children are discussed.     

The role of fear-avoidance and helplessness in explaining functional disability in chronic pain: a prospective study

Objective: Based on the fear-avoidance and helplessness models, the relative contribution of fear of pain, avoidance behavior, worrying, and helplessness were examined in relation to fluctuations in functional disability in chronic-pain patients. Methods: A cohort of 181 chronic-pain patients first completed various questionnaires and kept a 7-day pain journal during a standard 3-month waiting-list period prior to their scheduled treatment at an Interdisciplinary Pain Centre and did so again immediately preceding the intervention. Results: At baseline, fear of pain, avoidance behavior, and helplessness all predicted functional disability after 3 months. Stepwise regression analyses showed avoidance behavior to be the strongest predictor of change in functional disability followed by helplessness, thus both ahead of fear of pain. Conclusion: The current findings support the roles of both fear-avoidance factors and helplessness in the functional disability in chronic-pain patients awaiting treatment but revealed a central role for avoidance behavior.